Java example source code file (generation.cpp)
The generation.cpp Java example source code
/*
* Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "gc_implementation/shared/gcTimer.hpp"
#include "gc_implementation/shared/gcTrace.hpp"
#include "gc_implementation/shared/spaceDecorator.hpp"
#include "gc_interface/collectedHeap.inline.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/blockOffsetTable.inline.hpp"
#include "memory/cardTableRS.hpp"
#include "memory/gcLocker.inline.hpp"
#include "memory/genCollectedHeap.hpp"
#include "memory/genMarkSweep.hpp"
#include "memory/genOopClosures.hpp"
#include "memory/genOopClosures.inline.hpp"
#include "memory/generation.hpp"
#include "memory/generation.inline.hpp"
#include "memory/space.inline.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/java.hpp"
#include "utilities/copy.hpp"
#include "utilities/events.hpp"
Generation::Generation(ReservedSpace rs, size_t initial_size, int level) :
_level(level),
_ref_processor(NULL) {
if (!_virtual_space.initialize(rs, initial_size)) {
vm_exit_during_initialization("Could not reserve enough space for "
"object heap");
}
// Mangle all of the the initial generation.
if (ZapUnusedHeapArea) {
MemRegion mangle_region((HeapWord*)_virtual_space.low(),
(HeapWord*)_virtual_space.high());
SpaceMangler::mangle_region(mangle_region);
}
_reserved = MemRegion((HeapWord*)_virtual_space.low_boundary(),
(HeapWord*)_virtual_space.high_boundary());
}
GenerationSpec* Generation::spec() {
GenCollectedHeap* gch = GenCollectedHeap::heap();
assert(0 <= level() && level() < gch->_n_gens, "Bad gen level");
return gch->_gen_specs[level()];
}
size_t Generation::max_capacity() const {
return reserved().byte_size();
}
void Generation::print_heap_change(size_t prev_used) const {
if (PrintGCDetails && Verbose) {
gclog_or_tty->print(" " SIZE_FORMAT
"->" SIZE_FORMAT
"(" SIZE_FORMAT ")",
prev_used, used(), capacity());
} else {
gclog_or_tty->print(" " SIZE_FORMAT "K"
"->" SIZE_FORMAT "K"
"(" SIZE_FORMAT "K)",
prev_used / K, used() / K, capacity() / K);
}
}
// By default we get a single threaded default reference processor;
// generations needing multi-threaded refs processing or discovery override this method.
void Generation::ref_processor_init() {
assert(_ref_processor == NULL, "a reference processor already exists");
assert(!_reserved.is_empty(), "empty generation?");
_ref_processor = new ReferenceProcessor(_reserved); // a vanilla reference processor
if (_ref_processor == NULL) {
vm_exit_during_initialization("Could not allocate ReferenceProcessor object");
}
}
void Generation::print() const { print_on(tty); }
void Generation::print_on(outputStream* st) const {
st->print(" %-20s", name());
st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
capacity()/K, used()/K);
st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
_virtual_space.low_boundary(),
_virtual_space.high(),
_virtual_space.high_boundary());
}
void Generation::print_summary_info() { print_summary_info_on(tty); }
void Generation::print_summary_info_on(outputStream* st) {
StatRecord* sr = stat_record();
double time = sr->accumulated_time.seconds();
st->print_cr("[Accumulated GC generation %d time %3.7f secs, "
"%d GC's, avg GC time %3.7f]",
level(), time, sr->invocations,
sr->invocations > 0 ? time / sr->invocations : 0.0);
}
// Utility iterator classes
class GenerationIsInReservedClosure : public SpaceClosure {
public:
const void* _p;
Space* sp;
virtual void do_space(Space* s) {
if (sp == NULL) {
if (s->is_in_reserved(_p)) sp = s;
}
}
GenerationIsInReservedClosure(const void* p) : _p(p), sp(NULL) {}
};
class GenerationIsInClosure : public SpaceClosure {
public:
const void* _p;
Space* sp;
virtual void do_space(Space* s) {
if (sp == NULL) {
if (s->is_in(_p)) sp = s;
}
}
GenerationIsInClosure(const void* p) : _p(p), sp(NULL) {}
};
bool Generation::is_in(const void* p) const {
GenerationIsInClosure blk(p);
((Generation*)this)->space_iterate(&blk);
return blk.sp != NULL;
}
DefNewGeneration* Generation::as_DefNewGeneration() {
assert((kind() == Generation::DefNew) ||
(kind() == Generation::ParNew) ||
(kind() == Generation::ASParNew),
"Wrong youngest generation type");
return (DefNewGeneration*) this;
}
Generation* Generation::next_gen() const {
GenCollectedHeap* gch = GenCollectedHeap::heap();
int next = level() + 1;
if (next < gch->_n_gens) {
return gch->_gens[next];
} else {
return NULL;
}
}
size_t Generation::max_contiguous_available() const {
// The largest number of contiguous free words in this or any higher generation.
size_t max = 0;
for (const Generation* gen = this; gen != NULL; gen = gen->next_gen()) {
size_t avail = gen->contiguous_available();
if (avail > max) {
max = avail;
}
}
return max;
}
bool Generation::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const {
size_t available = max_contiguous_available();
bool res = (available >= max_promotion_in_bytes);
if (PrintGC && Verbose) {
gclog_or_tty->print_cr(
"Generation: promo attempt is%s safe: available("SIZE_FORMAT") %s max_promo("SIZE_FORMAT")",
res? "":" not", available, res? ">=":"<",
max_promotion_in_bytes);
}
return res;
}
// Ignores "ref" and calls allocate().
oop Generation::promote(oop obj, size_t obj_size) {
assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
#ifndef PRODUCT
if (Universe::heap()->promotion_should_fail()) {
return NULL;
}
#endif // #ifndef PRODUCT
HeapWord* result = allocate(obj_size, false);
if (result != NULL) {
Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
return oop(result);
} else {
GenCollectedHeap* gch = GenCollectedHeap::heap();
return gch->handle_failed_promotion(this, obj, obj_size);
}
}
oop Generation::par_promote(int thread_num,
oop obj, markOop m, size_t word_sz) {
// Could do a bad general impl here that gets a lock. But no.
ShouldNotCallThis();
return NULL;
}
void Generation::par_promote_alloc_undo(int thread_num,
HeapWord* obj, size_t word_sz) {
// Could do a bad general impl here that gets a lock. But no.
guarantee(false, "No good general implementation.");
}
Space* Generation::space_containing(const void* p) const {
GenerationIsInReservedClosure blk(p);
// Cast away const
((Generation*)this)->space_iterate(&blk);
return blk.sp;
}
// Some of these are mediocre general implementations. Should be
// overridden to get better performance.
class GenerationBlockStartClosure : public SpaceClosure {
public:
const void* _p;
HeapWord* _start;
virtual void do_space(Space* s) {
if (_start == NULL && s->is_in_reserved(_p)) {
_start = s->block_start(_p);
}
}
GenerationBlockStartClosure(const void* p) { _p = p; _start = NULL; }
};
HeapWord* Generation::block_start(const void* p) const {
GenerationBlockStartClosure blk(p);
// Cast away const
((Generation*)this)->space_iterate(&blk);
return blk._start;
}
class GenerationBlockSizeClosure : public SpaceClosure {
public:
const HeapWord* _p;
size_t size;
virtual void do_space(Space* s) {
if (size == 0 && s->is_in_reserved(_p)) {
size = s->block_size(_p);
}
}
GenerationBlockSizeClosure(const HeapWord* p) { _p = p; size = 0; }
};
size_t Generation::block_size(const HeapWord* p) const {
GenerationBlockSizeClosure blk(p);
// Cast away const
((Generation*)this)->space_iterate(&blk);
assert(blk.size > 0, "seems reasonable");
return blk.size;
}
class GenerationBlockIsObjClosure : public SpaceClosure {
public:
const HeapWord* _p;
bool is_obj;
virtual void do_space(Space* s) {
if (!is_obj && s->is_in_reserved(_p)) {
is_obj |= s->block_is_obj(_p);
}
}
GenerationBlockIsObjClosure(const HeapWord* p) { _p = p; is_obj = false; }
};
bool Generation::block_is_obj(const HeapWord* p) const {
GenerationBlockIsObjClosure blk(p);
// Cast away const
((Generation*)this)->space_iterate(&blk);
return blk.is_obj;
}
class GenerationOopIterateClosure : public SpaceClosure {
public:
ExtendedOopClosure* cl;
MemRegion mr;
virtual void do_space(Space* s) {
s->oop_iterate(mr, cl);
}
GenerationOopIterateClosure(ExtendedOopClosure* _cl, MemRegion _mr) :
cl(_cl), mr(_mr) {}
};
void Generation::oop_iterate(ExtendedOopClosure* cl) {
GenerationOopIterateClosure blk(cl, _reserved);
space_iterate(&blk);
}
void Generation::oop_iterate(MemRegion mr, ExtendedOopClosure* cl) {
GenerationOopIterateClosure blk(cl, mr);
space_iterate(&blk);
}
void Generation::younger_refs_in_space_iterate(Space* sp,
OopsInGenClosure* cl) {
GenRemSet* rs = SharedHeap::heap()->rem_set();
rs->younger_refs_in_space_iterate(sp, cl);
}
class GenerationObjIterateClosure : public SpaceClosure {
private:
ObjectClosure* _cl;
public:
virtual void do_space(Space* s) {
s->object_iterate(_cl);
}
GenerationObjIterateClosure(ObjectClosure* cl) : _cl(cl) {}
};
void Generation::object_iterate(ObjectClosure* cl) {
GenerationObjIterateClosure blk(cl);
space_iterate(&blk);
}
class GenerationSafeObjIterateClosure : public SpaceClosure {
private:
ObjectClosure* _cl;
public:
virtual void do_space(Space* s) {
s->safe_object_iterate(_cl);
}
GenerationSafeObjIterateClosure(ObjectClosure* cl) : _cl(cl) {}
};
void Generation::safe_object_iterate(ObjectClosure* cl) {
GenerationSafeObjIterateClosure blk(cl);
space_iterate(&blk);
}
void Generation::prepare_for_compaction(CompactPoint* cp) {
// Generic implementation, can be specialized
CompactibleSpace* space = first_compaction_space();
while (space != NULL) {
space->prepare_for_compaction(cp);
space = space->next_compaction_space();
}
}
class AdjustPointersClosure: public SpaceClosure {
public:
void do_space(Space* sp) {
sp->adjust_pointers();
}
};
void Generation::adjust_pointers() {
// Note that this is done over all spaces, not just the compactible
// ones.
AdjustPointersClosure blk;
space_iterate(&blk, true);
}
void Generation::compact() {
CompactibleSpace* sp = first_compaction_space();
while (sp != NULL) {
sp->compact();
sp = sp->next_compaction_space();
}
}
CardGeneration::CardGeneration(ReservedSpace rs, size_t initial_byte_size,
int level,
GenRemSet* remset) :
Generation(rs, initial_byte_size, level), _rs(remset),
_shrink_factor(0), _min_heap_delta_bytes(), _capacity_at_prologue(),
_used_at_prologue()
{
HeapWord* start = (HeapWord*)rs.base();
size_t reserved_byte_size = rs.size();
assert((uintptr_t(start) & 3) == 0, "bad alignment");
assert((reserved_byte_size & 3) == 0, "bad alignment");
MemRegion reserved_mr(start, heap_word_size(reserved_byte_size));
_bts = new BlockOffsetSharedArray(reserved_mr,
heap_word_size(initial_byte_size));
MemRegion committed_mr(start, heap_word_size(initial_byte_size));
_rs->resize_covered_region(committed_mr);
if (_bts == NULL)
vm_exit_during_initialization("Could not allocate a BlockOffsetArray");
// Verify that the start and end of this generation is the start of a card.
// If this wasn't true, a single card could span more than on generation,
// which would cause problems when we commit/uncommit memory, and when we
// clear and dirty cards.
guarantee(_rs->is_aligned(reserved_mr.start()), "generation must be card aligned");
if (reserved_mr.end() != Universe::heap()->reserved_region().end()) {
// Don't check at the very end of the heap as we'll assert that we're probing off
// the end if we try.
guarantee(_rs->is_aligned(reserved_mr.end()), "generation must be card aligned");
}
_min_heap_delta_bytes = MinHeapDeltaBytes;
_capacity_at_prologue = initial_byte_size;
_used_at_prologue = 0;
}
bool CardGeneration::expand(size_t bytes, size_t expand_bytes) {
assert_locked_or_safepoint(Heap_lock);
if (bytes == 0) {
return true; // That's what grow_by(0) would return
}
size_t aligned_bytes = ReservedSpace::page_align_size_up(bytes);
if (aligned_bytes == 0){
// The alignment caused the number of bytes to wrap. An expand_by(0) will
// return true with the implication that an expansion was done when it
// was not. A call to expand implies a best effort to expand by "bytes"
// but not a guarantee. Align down to give a best effort. This is likely
// the most that the generation can expand since it has some capacity to
// start with.
aligned_bytes = ReservedSpace::page_align_size_down(bytes);
}
size_t aligned_expand_bytes = ReservedSpace::page_align_size_up(expand_bytes);
bool success = false;
if (aligned_expand_bytes > aligned_bytes) {
success = grow_by(aligned_expand_bytes);
}
if (!success) {
success = grow_by(aligned_bytes);
}
if (!success) {
success = grow_to_reserved();
}
if (PrintGC && Verbose) {
if (success && GC_locker::is_active_and_needs_gc()) {
gclog_or_tty->print_cr("Garbage collection disabled, expanded heap instead");
}
}
return success;
}
// No young generation references, clear this generation's cards.
void CardGeneration::clear_remembered_set() {
_rs->clear(reserved());
}
// Objects in this generation may have moved, invalidate this
// generation's cards.
void CardGeneration::invalidate_remembered_set() {
_rs->invalidate(used_region());
}
void CardGeneration::compute_new_size() {
assert(_shrink_factor <= 100, "invalid shrink factor");
size_t current_shrink_factor = _shrink_factor;
_shrink_factor = 0;
// We don't have floating point command-line arguments
// Note: argument processing ensures that MinHeapFreeRatio < 100.
const double minimum_free_percentage = MinHeapFreeRatio / 100.0;
const double maximum_used_percentage = 1.0 - minimum_free_percentage;
// Compute some numbers about the state of the heap.
const size_t used_after_gc = used();
const size_t capacity_after_gc = capacity();
const double min_tmp = used_after_gc / maximum_used_percentage;
size_t minimum_desired_capacity = (size_t)MIN2(min_tmp, double(max_uintx));
// Don't shrink less than the initial generation size
minimum_desired_capacity = MAX2(minimum_desired_capacity,
spec()->init_size());
assert(used_after_gc <= minimum_desired_capacity, "sanity check");
if (PrintGC && Verbose) {
const size_t free_after_gc = free();
const double free_percentage = ((double)free_after_gc) / capacity_after_gc;
gclog_or_tty->print_cr("TenuredGeneration::compute_new_size: ");
gclog_or_tty->print_cr(" "
" minimum_free_percentage: %6.2f"
" maximum_used_percentage: %6.2f",
minimum_free_percentage,
maximum_used_percentage);
gclog_or_tty->print_cr(" "
" free_after_gc : %6.1fK"
" used_after_gc : %6.1fK"
" capacity_after_gc : %6.1fK",
free_after_gc / (double) K,
used_after_gc / (double) K,
capacity_after_gc / (double) K);
gclog_or_tty->print_cr(" "
" free_percentage: %6.2f",
free_percentage);
}
if (capacity_after_gc < minimum_desired_capacity) {
// If we have less free space than we want then expand
size_t expand_bytes = minimum_desired_capacity - capacity_after_gc;
// Don't expand unless it's significant
if (expand_bytes >= _min_heap_delta_bytes) {
expand(expand_bytes, 0); // safe if expansion fails
}
if (PrintGC && Verbose) {
gclog_or_tty->print_cr(" expanding:"
" minimum_desired_capacity: %6.1fK"
" expand_bytes: %6.1fK"
" _min_heap_delta_bytes: %6.1fK",
minimum_desired_capacity / (double) K,
expand_bytes / (double) K,
_min_heap_delta_bytes / (double) K);
}
return;
}
// No expansion, now see if we want to shrink
size_t shrink_bytes = 0;
// We would never want to shrink more than this
size_t max_shrink_bytes = capacity_after_gc - minimum_desired_capacity;
if (MaxHeapFreeRatio < 100) {
const double maximum_free_percentage = MaxHeapFreeRatio / 100.0;
const double minimum_used_percentage = 1.0 - maximum_free_percentage;
const double max_tmp = used_after_gc / minimum_used_percentage;
size_t maximum_desired_capacity = (size_t)MIN2(max_tmp, double(max_uintx));
maximum_desired_capacity = MAX2(maximum_desired_capacity,
spec()->init_size());
if (PrintGC && Verbose) {
gclog_or_tty->print_cr(" "
" maximum_free_percentage: %6.2f"
" minimum_used_percentage: %6.2f",
maximum_free_percentage,
minimum_used_percentage);
gclog_or_tty->print_cr(" "
" _capacity_at_prologue: %6.1fK"
" minimum_desired_capacity: %6.1fK"
" maximum_desired_capacity: %6.1fK",
_capacity_at_prologue / (double) K,
minimum_desired_capacity / (double) K,
maximum_desired_capacity / (double) K);
}
assert(minimum_desired_capacity <= maximum_desired_capacity,
"sanity check");
if (capacity_after_gc > maximum_desired_capacity) {
// Capacity too large, compute shrinking size
shrink_bytes = capacity_after_gc - maximum_desired_capacity;
// We don't want shrink all the way back to initSize if people call
// System.gc(), because some programs do that between "phases" and then
// we'd just have to grow the heap up again for the next phase. So we
// damp the shrinking: 0% on the first call, 10% on the second call, 40%
// on the third call, and 100% by the fourth call. But if we recompute
// size without shrinking, it goes back to 0%.
shrink_bytes = shrink_bytes / 100 * current_shrink_factor;
assert(shrink_bytes <= max_shrink_bytes, "invalid shrink size");
if (current_shrink_factor == 0) {
_shrink_factor = 10;
} else {
_shrink_factor = MIN2(current_shrink_factor * 4, (size_t) 100);
}
if (PrintGC && Verbose) {
gclog_or_tty->print_cr(" "
" shrinking:"
" initSize: %.1fK"
" maximum_desired_capacity: %.1fK",
spec()->init_size() / (double) K,
maximum_desired_capacity / (double) K);
gclog_or_tty->print_cr(" "
" shrink_bytes: %.1fK"
" current_shrink_factor: %d"
" new shrink factor: %d"
" _min_heap_delta_bytes: %.1fK",
shrink_bytes / (double) K,
current_shrink_factor,
_shrink_factor,
_min_heap_delta_bytes / (double) K);
}
}
}
if (capacity_after_gc > _capacity_at_prologue) {
// We might have expanded for promotions, in which case we might want to
// take back that expansion if there's room after GC. That keeps us from
// stretching the heap with promotions when there's plenty of room.
size_t expansion_for_promotion = capacity_after_gc - _capacity_at_prologue;
expansion_for_promotion = MIN2(expansion_for_promotion, max_shrink_bytes);
// We have two shrinking computations, take the largest
shrink_bytes = MAX2(shrink_bytes, expansion_for_promotion);
assert(shrink_bytes <= max_shrink_bytes, "invalid shrink size");
if (PrintGC && Verbose) {
gclog_or_tty->print_cr(" "
" aggressive shrinking:"
" _capacity_at_prologue: %.1fK"
" capacity_after_gc: %.1fK"
" expansion_for_promotion: %.1fK"
" shrink_bytes: %.1fK",
capacity_after_gc / (double) K,
_capacity_at_prologue / (double) K,
expansion_for_promotion / (double) K,
shrink_bytes / (double) K);
}
}
// Don't shrink unless it's significant
if (shrink_bytes >= _min_heap_delta_bytes) {
shrink(shrink_bytes);
}
}
// Currently nothing to do.
void CardGeneration::prepare_for_verify() {}
void OneContigSpaceCardGeneration::collect(bool full,
bool clear_all_soft_refs,
size_t size,
bool is_tlab) {
GenCollectedHeap* gch = GenCollectedHeap::heap();
SpecializationStats::clear();
// Temporarily expand the span of our ref processor, so
// refs discovery is over the entire heap, not just this generation
ReferenceProcessorSpanMutator
x(ref_processor(), gch->reserved_region());
STWGCTimer* gc_timer = GenMarkSweep::gc_timer();
gc_timer->register_gc_start();
SerialOldTracer* gc_tracer = GenMarkSweep::gc_tracer();
gc_tracer->report_gc_start(gch->gc_cause(), gc_timer->gc_start());
GenMarkSweep::invoke_at_safepoint(_level, ref_processor(), clear_all_soft_refs);
gc_timer->register_gc_end();
gc_tracer->report_gc_end(gc_timer->gc_end(), gc_timer->time_partitions());
SpecializationStats::print();
}
HeapWord*
OneContigSpaceCardGeneration::expand_and_allocate(size_t word_size,
bool is_tlab,
bool parallel) {
assert(!is_tlab, "OneContigSpaceCardGeneration does not support TLAB allocation");
if (parallel) {
MutexLocker x(ParGCRareEvent_lock);
HeapWord* result = NULL;
size_t byte_size = word_size * HeapWordSize;
while (true) {
expand(byte_size, _min_heap_delta_bytes);
if (GCExpandToAllocateDelayMillis > 0) {
os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
}
result = _the_space->par_allocate(word_size);
if ( result != NULL) {
return result;
} else {
// If there's not enough expansion space available, give up.
if (_virtual_space.uncommitted_size() < byte_size) {
return NULL;
}
// else try again
}
}
} else {
expand(word_size*HeapWordSize, _min_heap_delta_bytes);
return _the_space->allocate(word_size);
}
}
bool OneContigSpaceCardGeneration::expand(size_t bytes, size_t expand_bytes) {
GCMutexLocker x(ExpandHeap_lock);
return CardGeneration::expand(bytes, expand_bytes);
}
void OneContigSpaceCardGeneration::shrink(size_t bytes) {
assert_locked_or_safepoint(ExpandHeap_lock);
size_t size = ReservedSpace::page_align_size_down(bytes);
if (size > 0) {
shrink_by(size);
}
}
size_t OneContigSpaceCardGeneration::capacity() const {
return _the_space->capacity();
}
size_t OneContigSpaceCardGeneration::used() const {
return _the_space->used();
}
size_t OneContigSpaceCardGeneration::free() const {
return _the_space->free();
}
MemRegion OneContigSpaceCardGeneration::used_region() const {
return the_space()->used_region();
}
size_t OneContigSpaceCardGeneration::unsafe_max_alloc_nogc() const {
return _the_space->free();
}
size_t OneContigSpaceCardGeneration::contiguous_available() const {
return _the_space->free() + _virtual_space.uncommitted_size();
}
bool OneContigSpaceCardGeneration::grow_by(size_t bytes) {
assert_locked_or_safepoint(ExpandHeap_lock);
bool result = _virtual_space.expand_by(bytes);
if (result) {
size_t new_word_size =
heap_word_size(_virtual_space.committed_size());
MemRegion mr(_the_space->bottom(), new_word_size);
// Expand card table
Universe::heap()->barrier_set()->resize_covered_region(mr);
// Expand shared block offset array
_bts->resize(new_word_size);
// Fix for bug #4668531
if (ZapUnusedHeapArea) {
MemRegion mangle_region(_the_space->end(),
(HeapWord*)_virtual_space.high());
SpaceMangler::mangle_region(mangle_region);
}
// Expand space -- also expands space's BOT
// (which uses (part of) shared array above)
_the_space->set_end((HeapWord*)_virtual_space.high());
// update the space and generation capacity counters
update_counters();
if (Verbose && PrintGC) {
size_t new_mem_size = _virtual_space.committed_size();
size_t old_mem_size = new_mem_size - bytes;
gclog_or_tty->print_cr("Expanding %s from " SIZE_FORMAT "K by "
SIZE_FORMAT "K to " SIZE_FORMAT "K",
name(), old_mem_size/K, bytes/K, new_mem_size/K);
}
}
return result;
}
bool OneContigSpaceCardGeneration::grow_to_reserved() {
assert_locked_or_safepoint(ExpandHeap_lock);
bool success = true;
const size_t remaining_bytes = _virtual_space.uncommitted_size();
if (remaining_bytes > 0) {
success = grow_by(remaining_bytes);
DEBUG_ONLY(if (!success) warning("grow to reserved failed");)
}
return success;
}
void OneContigSpaceCardGeneration::shrink_by(size_t bytes) {
assert_locked_or_safepoint(ExpandHeap_lock);
// Shrink committed space
_virtual_space.shrink_by(bytes);
// Shrink space; this also shrinks the space's BOT
_the_space->set_end((HeapWord*) _virtual_space.high());
size_t new_word_size = heap_word_size(_the_space->capacity());
// Shrink the shared block offset array
_bts->resize(new_word_size);
MemRegion mr(_the_space->bottom(), new_word_size);
// Shrink the card table
Universe::heap()->barrier_set()->resize_covered_region(mr);
if (Verbose && PrintGC) {
size_t new_mem_size = _virtual_space.committed_size();
size_t old_mem_size = new_mem_size + bytes;
gclog_or_tty->print_cr("Shrinking %s from " SIZE_FORMAT "K to " SIZE_FORMAT "K",
name(), old_mem_size/K, new_mem_size/K);
}
}
// Currently nothing to do.
void OneContigSpaceCardGeneration::prepare_for_verify() {}
// Override for a card-table generation with one contiguous
// space. NOTE: For reasons that are lost in the fog of history,
// this code is used when you iterate over perm gen objects,
// even when one uses CDS, where the perm gen has a couple of
// other spaces; this is because CompactingPermGenGen derives
// from OneContigSpaceCardGeneration. This should be cleaned up,
// see CR 6897789..
void OneContigSpaceCardGeneration::object_iterate(ObjectClosure* blk) {
_the_space->object_iterate(blk);
}
void OneContigSpaceCardGeneration::space_iterate(SpaceClosure* blk,
bool usedOnly) {
blk->do_space(_the_space);
}
void OneContigSpaceCardGeneration::younger_refs_iterate(OopsInGenClosure* blk) {
blk->set_generation(this);
younger_refs_in_space_iterate(_the_space, blk);
blk->reset_generation();
}
void OneContigSpaceCardGeneration::save_marks() {
_the_space->set_saved_mark();
}
void OneContigSpaceCardGeneration::reset_saved_marks() {
_the_space->reset_saved_mark();
}
bool OneContigSpaceCardGeneration::no_allocs_since_save_marks() {
return _the_space->saved_mark_at_top();
}
#define OneContig_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
\
void OneContigSpaceCardGeneration:: \
oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) { \
blk->set_generation(this); \
_the_space->oop_since_save_marks_iterate##nv_suffix(blk); \
blk->reset_generation(); \
save_marks(); \
}
ALL_SINCE_SAVE_MARKS_CLOSURES(OneContig_SINCE_SAVE_MARKS_ITERATE_DEFN)
#undef OneContig_SINCE_SAVE_MARKS_ITERATE_DEFN
void OneContigSpaceCardGeneration::gc_epilogue(bool full) {
_last_gc = WaterMark(the_space(), the_space()->top());
// update the generation and space performance counters
update_counters();
if (ZapUnusedHeapArea) {
the_space()->check_mangled_unused_area_complete();
}
}
void OneContigSpaceCardGeneration::record_spaces_top() {
assert(ZapUnusedHeapArea, "Not mangling unused space");
the_space()->set_top_for_allocations();
}
void OneContigSpaceCardGeneration::verify() {
the_space()->verify();
}
void OneContigSpaceCardGeneration::print_on(outputStream* st) const {
Generation::print_on(st);
st->print(" the");
the_space()->print_on(st);
}
Other Java examples (source code examples)Here is a short list of links related to this Java generation.cpp source code file: |
The search page
Other Java source code examples at this package level
Click here to learn more about this project
